1. Field of the Invention
The present invention relates to an inkjet printing apparatus.
2. Description of the Related Art
An inkjet printing apparatus forms an image by ejecting ink supplied from an ink tank and causing the ink to adhere to a print medium. In inkjet printing apparatus, a detector that detects the amount of remaining ink is typically provided in order to prevent faulty printing due to insufficient ink. More specifically, a detector is provided in an ink tank (i.e., the ink supply source), or in the case of a serial printing apparatus, in an ink sub-tank installed on a carriage where a print head is mounted.
If a remaining ink detector is provided in an ink tank, the detector is replaced every time the ink tank is replaced, which is wasteful and expensive as a result. Also, in the case where a remaining ink detector is provided in an ink sub-tank on a carriage, there is a possibility that incorrect operation may occur due to swaying of the ink surface during carriage displacement or that the reliability of electrically connecting parts may lower since such connecting parts also move with the carriage.
Japanese Patent Laid-Open No. S63-153147 (1988) discloses an inkjet printing apparatus provided with a remaining ink detector partway along an ink supply line. A remaining ink detection method disclosed in this publication requires a detector for each ink. For this reason, in the case of increasing the number of ink colors, all detector-related parts must be separately provided for each ink color, and costs increase. Also, in the case where the remaining amount must be successively detected for each color, for example, the time taken to detect the remaining amounts for all inks becomes the product of the remaining ink detection time for one color times the number of ink colors, and total printing time increases.